Why the Pulitzer Prize-winning playwright decided to rewrite part of his masterpiece again.

Despite having won a Pulitzer Prize for part one of his play Angels in America, Tony Kushner has been tinkering with the second part of the piece, Perestroika, ever since its premiere on Broadway in 1993. At the opening night of Marianne Elliott's new revival of the epic masterpiece, Kushner discussed the new changes he's made to the play, and told us why the great work is never done.